Oxide composite prepared from intermetallic and amorphous Zr₆₇Fe₃₀M_3- (M=Au, Pt) alloys and their catalytic activity for CO oxidation

In this study, Zr₆₇Fe₃₀M₃ (M=Au, Pt) intermetallic compounds and amorphous alloys were prepared and used as precursors for the synthesis of oxides. Oxidation treatment of the intermetallic compounds at 500 °C followed by X-ray diffraction (XRD) analysis indicated that zirconium and iron were oxidized to ZrO₂ and Fe₂O₃, respectively. In the case of Zr₆₇Fe₃₀M₃ amorphous alloys, cubic Zr₆Fe₃O was observed on the surface of the ribbons after heat treatment at 500 °C in vacuum. Addition of 3% of gold or platinum to the alloy resulted in an increase in the lattice constants of the Zr₆Fe₃O phase. Grounding the treated ribbons into powders followed by an oxidation treatment at 500 °C in air produced Fe₂O₃ and ZrO₂ supports, where Au and Pt are dissolved in the oxides as confirmed by X-ray photoelectron spectroscopy (XPS). No matter precursors are intermetallics or amorphous phases, the resultant oxides are the same. Although Pt and Au dissolved in the oxides, catalytic activities for CO oxidation were significant improved.